This invention relates generally to aromatic ketones and more specifically to bis-benzoins.
Poly[2,2'-(1,4-phenylene)-6,6'-bis(3-phenylquinoxaline)] and poly[2,2'-(1,3-phenylene)-6,6'-bis(3-phenylquinoxaline)] are useful as coatings for fibers, graphite precursors, films and laminating materials. These polymers possess two excellent properties: high thermal stability and good solubility in many organic solvents. This second property permits coatings of these polymers to be applied without heat curing. Further, it permits components coated with these polymers to be inspected by desolving the coating with ordinary organic solvents.
The above-mentioned polymers are synthesized by reacting 3,3'-diaminobenzidine with either 1,4-bis(phenylglyoxaloyl) benzene, i.e., p-phenylglyoxyloyl benzil, or with 1,3-bis(phenylglyoxaloyl) benzene, i.e., m-phenylglyoxyloyl benzil, by the method disclosed by W. Wrasidlo and J. M. Augl in "Phenylated Polyquinoxalines from Bis(phenylglyoxaloyl)Benzene," Journal of Polymer Science: Part A-1 Volume 7 (1965) PP. 3393-3405. This article also discloses a method of preparing the 1,4-bis(phenylglyoxaloyl) benzene and 1,3-bis(phenylglyoxalyl) benzene. Likewise, articles by J. Schmitt et al, Bull Soc. Chim. France, 636 (1956), and M. A. Ogliaruso and E. I. Becker, J. Org. Chem. 30, 3354 (1965) disclose methods which may be used to prepare these bis-.alpha.-diketones. Unfortunately, these prior art processes produce the bis-.alpha.-diketones in low yields using expensive starting materials or many separate reaction steps. Moreover, in many cases the product bis-.alpha.-diketones can only be purified with difficulty.